1. Field of the Invention
This invention relates to a process for separation of radioactive particles from aqueous suspensions and subsequent encapsulation of the particles. More particularly, it relates to the separation of radioactive particles from aqueous suspensions by filtration and subsequent encapsulation of the separated particles in a matrix comprised of a thermoplastic synthetic organic polymer.
2. Description of the Prior Art
In the filtration of industrial waste water and process water, it is customary to use a precoated filter prepared by initially depositing a filter aid on the surface of a relatively large-pore filter medium, e.g., a filter cloth, filter plate, filter cartridge or the like. The filter aids used in such processes can be organic materials, e.g., cellulose, or inorganic materials, e.g., asbestos, bentonite, and the like. Such filter aids are commercially available, for example, under the trademarks LEVASORB, AF 2, and SOLCA-FLOC, among others. After the filter aid has been used in the filtration of the water, it is generally burned or discarded together with the filtered solids. This filtering process using precoated filters and filter aids is satisfactory for the treatment of ordinary water and waste water containing suspended solids since it is effective and economical.
However, the known methods of filtration using precoated filters and/or filter aids are disadvantageous for treating water containing radioactive solids, because if the filter cake (filter aid and filtered solids) is burned a radioactive dust is produced, and, if it is not burned, it must be compressed, dried, and impregnated with bitumen before it is suitable for disposal by storage in steel drums and/or concrete containers.
In the operation of a medium-sized nuclear power plant having a capacity of 600 MW, about 40-50 kg of filter aid would be required for filtration of the radioactive process water (rad waste). Therefore, a relatively large volume of filter cake would be produced. Furthermore, it must be kept in mind that the usual filter aids in the form of cellulose fibers swell in water, with consequent difficulty in drying them, and that impregnation of the resulting dry and voluminous mass with bitumen presents problems.
Hence, a need has continued to exist for a method of easily removing radioactive particles from aqueous suspensions and encapsulating them in a thermoplastic matrix.